The invention set forth in this specification pertains to new and improved movable instruments which are provided with light emitting position indicators.
Although such instruments can be constructed so as to be utilized for a variety of different purposes it is preferred to utilize the present invention in connection with instruments employed in determining the temperature at a specific area of a surface. Hand-held movable instruments for use in measuring the temperature at various areas on a surface are considered to be well known. Normally in utilizing such instruments it is desired to obtain a temperature reading indicating the temperature at either the hottest or the coldest spot on such a surface. In order to direct or point the instrument toward such a spot it is necessary to monitor the temperature at various different adjacent locations on the surface until the instrument is held so that the sensor used in the instrument is pointed at either the hottest or the coldest spot on such a surface. In effect this operation involves detecting the differences in the temperature between adjacent locations or areas on the surface as the instrument is used.
Such instruments can of course be constructed in a number of different ways. They can be constructed so as to utilize a D'Arsonval meter movement in order to provide an analog indication of the difference in the temperature of adjacent areas of a surface and in order to provide a direct readout as to the temperature at any specific area. The use of such meters is considered undesirable and disadvantageous because D'Arsonval movements tend to be relatively expensive, because such movements normally are capable of being easily damaged, and because it is frequently difficult to read such a meter with a desired degree of accuracy. As a result of these factors instruments of the type described normally are now constructed so as to utilize a digital readout instead of a D'Arsonval meter movement.
In many ways this is considered to be highly advantageous. Such digital readouts are relatively inexpensive. They are not as prone to physical damage as D'Arsonval meter movements. Further, they are capable of being accurately read with a minimum of difficulty. However, they are less desirable than D'Arsonval meters in one regard. The response time of such a digital readout as an instrument as noted is used is relatively slow.
This makes it comparatively difficult for a movable instrument such as one used to obtain temperature readings to be directed at either the hottest or coldest spot or area on a surface with a minimum amount of time. Although it would be possible to utilize a D'Arsonval meter movement in conjunction with a digital readout so as to facilitate directing a hand-held movable instrument in a desired manner this is disadvantageous because of the cost of a D'Arsonval movement, because of the fact that such movement may be damaged relatively easily, and because of the slow response time of such a movement.